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Assessing Fukushima, one year later

Despite worries, radiation exposure from the Japanese nuclear plant damaged by the tsunami is unlikely to cause an increase in cancers. (…) This doesn’t mean there will be no future radiation-caused cancers, as some claim. But because there may be so few cancers, it is unlikely any epidemiological investigations will detect an increase in Japan or elsewhere that can be directly attributed to Fukushima.

(…) What do the Fukushima exposures really mean? A rough estimate is that for a 50-year-old male working at the Fukushima nuclear facility, his lifetime risk of cancer might increase from 42% to 42.2%. The magnitude of this increased risk is comparable to the added risk of living in Denver (where background radiation is higher because of the altitude and radionuclides in the Rocky Mountains) versus New York City for 10 to 15 years, or smoking one pack of cigarettes a day for one to two years. The Japanese public will, of course, get far less radiation.

(…) we think the public deserves an estimate of likely outcomes of radiation released when the March 11, 2011, earthquake and tsunami caused multiple meltdowns of nuclear fuel at the plant.

Fukushima has understandably reignited debate and concern regarding cancer risks from radiation. A year after the accident, many people still won’t travel to Japan. Sushi sales have taken a hit. And yet the Japanese government says that even those who lived near the reactor have little to worry about. Who’s right?

(…) In general, we don’t think much about the inherent risks of such exposures. For example, if your doctor sends you for a CT scan, you may get a radiation dose about seven times greater than you would in a year from most natural or man-made sources. However, few people decline a CT scan because of the risk of radiation-induced cancer. But when we read of a spike in the amount of radiation in the water in Tokyo, we get scared.

One important element that we have to consider to assess cancer risks associated with an accident like Fukushima is our baseline risk for developing cancer. All of us, unfortunately, have a substantial risk of developing cancer in our lifetime. For example, a 50-year-old male has a 42% risk of developing cancer during his remaining life; it’s almost the same for a 10-year-old. This risk only decreases when we get much older and only because we are dying of other causes.

It’s true that excess radiation exposure can increase our cancer risk above baseline levels; it’s clear from studies of the survivors of the 1945 atomic bombings of Hiroshima and Nagasaki, of people exposed to radiation in medical and occupational settings, and of people exposed to radon decay products in mines and home basements. When it comes to exposures like that of Fukushima, the question is: What is the relative magnitude of the increased risk from Fukushima compared to our baseline cancer risk? Despite our fears, it is quite small.

(…) Now for Fukushima. The kind of radiation was similar to Chernobyl, but about four to 10 times less was released. And there are other important differences. Most of the radiation released (about 80%) was blown offshore by winds, where it was diluted by air and sea. Consequently, exposures received by Fukushima workers and the public are quite low, including among the 20,000 or more workers decommissioning the facility and the approximately 100,000 evacuees. This doesn’t mean there will be no future radiation-caused cancers, as some claim. But because there may be so few cancers, it is unlikely any epidemiological investigations will detect an increase in Japan or elsewhere that can be directly attributed to Fukushima.

(…) Robert Peter Gale, a visiting professor of hematology at Imperial College London, is involved with the aftermath of the Chernobyl and Fukushima accidents. F. Owen Hoffman is an expert in radiation risk assessment working in Oak Ridge, Tenn.

From his CV, some background on leukemia specialist Robert Peter Gale, particularly his relevant experience with the medical effects of radiation:

In 1986, he was asked by the government Soviet Union to coordinate medical relief efforts for victims of the Chernobyl nuclear power station accident. In 1987, he was asked by the government of Brazil to coordinate medical relief efforts for a radiation accident in Goiania. In 1988, he was part of the U.S. medical emergency team sent in the aftermath of the earthquake in Armenia. In 1999 he was asked by the government of Japan to help treat victims of the nuclear criticality accident near Tokyo. In 2011 Gale was called to Japan to deal with medical consequences of the Fukushima nuclear power station accident.

He has more than 30 years experience on the evaluation of the dose to humans from the release and transport of radionuclides and chemicals in terrestrial and aquatic systems. He is recognized nationally and internationally for his contributions to the development and evaluation of mathematical models for environmental transfer and human risk assessment.